Cell surface antigen induced by influenza virus

Fixed-cell immunoperoxidase technique for the study of surface antigens induced by the coronavirus of transmissible gastroenteritis (TGEV)

An immunoperoxidase technique performed on the TGEV-infected cells was developed for detection of virus-induced antigens. The presence of M antigen of TGEV on the surface of infected cells was demonstrated by this technique. This finding is in contrast to the M protein of murine hepatitis coronavirus which migrates to the Golgi apparatus but is not transported to the plasma membrane. The time course of appearance M and S antigens on the surface of TGEV-infected cell can be studied by this technique.

Surface antigens on HeLa cells persistently infected with HVJ (Sendai virus)

Surface antigens of HeLaHVJ cells, a cell line persistently infected with HVJ, were studied by fluorescent antibody staining. After absorption with concentrated HVJ virions and HeLa cells, anti-HeLaHVJ antiserum was able to demonstrate specific surface fluorescence on HeLaHVJ cells, while this serum no longer reacted with original HeLa cells nor with HVJ virions. During cytolytic infection of HeLa cells with HVJ, this specific surface antigen appeared at an early stage of infection prior to the appearance of newly synthesized HVJ viral antigens and moreover appeared in spite of the inhibition of viral protein synthesis. This antigen was detected neither on HeLa cells infected with other myxoviruses except HVJ nor on various other kinds of cells infected with HVJ. The specific surface antigen was still found on the HeLaHVJ cell surface after incubation at 38 degrees C for two days, while HVJ structural antigens on the cell surface no longer could be detected. Mild short-term treatment of HeLa cells with trypsin, neuraminidase from vibrio cholerae, phospholipase-C and hyaluronidase failed to expose specific antigen. The antigen was distinguishable from the Forssman and human blood type antigens. The mechanism of appearance of a new antigen on the surface of HeLaHVJ cells remains unclear.

Immunization of ferrets against influenza: a comparison of killed ferret grown and egg grown virus

Both killed unadjuvanted ferret and egg grown A/Moscow/1019/65 (H₂N₂) influenza virus failed to immunize ferrets against challenge with homologous virus; the preparations were given in 2 doses, 2 weeks apart, distributed intranasally, intramuscularly and intraperitoneally. However, small doses (<2 HA units) of both preparations induced immunity in ferrets previously “primed” with a live heterologous virus (A/FM/1/47 (H₁N₁)) according to the method of Potter et al. (1973a, b). Although no difference in immunizing activity was detected between ferret and egg grown virus, the former induced greater HI titres than the latter. There was no correlation between HI titres in serum and protection to challenge; in fact, some protection seemed to be afforded by the “priming” virus in the absence of HI antibody to the challenge virus.

These results are discussed in relation to the possibility that a previously unrecognized antigen different from haemagglutinin and neuraminidase may contribute to immunity to influenza.

Quantitative assessment of hemadsorption by myxoviruses: virus hemadsorption assay

The standardization and quantitative evaluation of an assay for myxoviruses, based on the enumeration of individual infected clone 1-5C-4 cells manifesting hemadsorption within 24 h of infection, are described. Hemadsorption was detectable earlier than immunofluorescence in infected cells or hemagglutinins in culture medium. The relationship between virus concentration and cells exhibiting hemadsorption was linear. The assay was highly precise, sensitive, and reproducible.